Inductance coil



Och-6, 1931. H. w. ADEY INDUCTANCE COIL Filed Oct. I5, 1929 INVENTOR' Horace H. Aday, BY' %7// ATTO we} Patented Oct. 6 1931 PATENT OFFICE HORACE WILLIAM ADEY, or Lennon, ENGLAND INDUCTANCE coir.

Application filed October 8, 1929, Serial No. 397,091, and in Great Britain November 3,1928.

This invention relates to a coil and coil holder for use with radio receiving and transmitting apparatus and for like purposes, and particularly for radio apparatus of the kind wherein there is employed what is termed a loop or frame aerial or antenna, 2'. e. an aerial consisting of an open coil arranged for example around the case containing the remaining apparatus of the set, and wherein such loop or frame aerial is utilized as one of-the coils of a variable inductance, as described in the specification of my application, Serial No. 397,092, filed October 3,1929.

According to this invention a coil which may advantageously form the other or movable coil of the variable inductance or loose coupling device, is provided with coaxially arranged contacts to which the ends of the wire or wires forming the coil are respectively connected, the said coil being adapted to be introduced into a receiving or transmitting circuit by the insert-ion of the coaxially arranged contacts into a suitably arranged socket having correspondingly arrangedcontacts associated therewith.

The coil may consist of a single loop or convolution of steel, copper, brass or other suitable metal, or it may consist of a coil having any desired number of convolutions in close or open windingor it may be wound part one way and part the other way with a central tapping. If desired however in order to vary easily the number of operative convolutions of the coil, a tapped coil may be employed which is connected to a series of metal studs or contacts which cooperate with a switch arm connected to one of the coaxially arranged contacts hereinbefore referred to.

In the accompanying drawings, which show by way of example how the said invention may be carried into practice,

Figure 1 is a sectional view of a coil and coil holder; and

Figure 2 is an elevation of a modified arrangement.

As shown in Figure 1, a coil 1 is mounted upon a coil holder 2 of insulating material,

and has one end thereof connected to a metal strip 3 which is maintained in electrical contact with a tubular metal member 4. The

other end of the coil is connected to a metal strip 5- secured upon an insulated metallic rod 6 which terminates, e. g. in a ball head 7. The metal rod is also provided with a flange 8, the diameter of which may be substantially equal to the external diameter of the tubular member 4. Washers9 of insulating material are inserted between the tubular member 4 and the rod 6 in order to ensure that these members are electrically insulated one from another, but any other suitable arrangementof the insulation may be employed. The stem formed by the concentric contacts, 6. g. 4 and 7, may be of any suitable form in cross-section, e. round, square, hexagonal, oval or lozenge shape, and the contacts may be of any desired length.

The coil 1 may consist of a single loop or convolution of steel, copper, brass or other suitable metal, or it may consist of a coil having any desired number of convolutions in close or open winding, or it may be wound partlyone way and partly the other way with a central tapping which is connected to one of the metal strips.

In order to vary easily'the number of operative convolutions of the coil, a tapped coil 10, Figure 2 may be employed. The tappings of the coil 10 are connected to a series of metal studs or contacts 11 which cooperate with a switch arm 12 connected to the strip 3. The metal studs or contacts, and the switch arm may be arranged in any suitable position upon the coil holder.

I claim:

1. An inductance coil for use with radio receiving and transmitting apparatus, comprising a coil holder of insulating material,- a metal tubular member secured to said coil holder, a metal rod arranged coaxially with said tubular member, means for insulating said rod from the tubular member, metal strips arranged within the coil holder and respectively secured to the tubular member and the metal rod, and a coil having its terminals respectively connected to the tubular member and to the said metal rod through said metal strips.

2. An inductance coil for use with radio receiving and transmitting apparatus, comprising a coil holder of insulating material, a metal tubular member secured to said coil holder, a metal rod terminating in a ball head and provided with a flange having a diameter equal to the external diameter of the metal tubular member, means for insulating said rod from said tubular member and maintaining them in coaxial positions, metal strips arranged within the coil holder and respectively connected to the tubular member and to the metal rod, and a coil having its terminals respectively connected to the tubular member and to the said metal rod through said metal strips.

3. An inductance coil for use with radio receiving and transmitting apparatus, comprising a coil holder of insulating material, a metal tubular member secured to said holder, a metal rod arranged coaxially with said tubular member, means for insulating said rod from said tubular member, two metal strips arranged Within the coil holder and respectively connected to the tubular member and to the metal rod, a series of studs arranged on said coil holder, amovable switch arm associated with said studs and connected to one of said metal strips, and a tapped coil mounted on said coil holder and having its tapping points connected to the series of studs arranged on the coil holder.

HORACE WVILLIAM ADEY. 

